A flux-cored or solid welding wire which is used in an arc welding operation and which may have a diameter in a range from 0.6 to 2.4 mm is prepared in the form of laminated coil winding. Thus the welding wire is coiled into a cylindrical or doughnut-shaped configuration, and one unit thereof weighs from 1 to 20 kg and has an inner coil diameter of 50 to 180 mm .phi. and a coil width of 40 to 100 mm.
Such a welding wire coil may be coiled around a winding form such as a reel, spool or the like (as disclosed, for example, in Japanese Laid-Open Patent Applications No. 10,346/1983 and No. 19,646/1987) or the winding form may be removed upon completion of the winding operation to leave the wire coil in a form bundled with bundling wires, wide steel bands, plastic bands or the like. Alternatively, Japanese Laid-Open Patent Application No. 84,573/1993 discloses a coil which is formed without the use of a winding form such as a reel and which is subsequently constrained by removable retainers. U-shaped needles or springy clip-shaped metal wire jigs are illustrated for use as such constraining retainers. Japanese Laid-Open Patent Application No. 278,714/1994 discloses a technique which wraps a coil with an enclosure of composite aluminum film, which is then degassed and sealed.
For use, it is necessary to pay out the wire from the coil in a manner to avoid an entanglement of the wire, which is likely to occur if the coil configuration is collapsed. Accordingly, it is required to protect the coil against deformation when it is being conveyed.
For a coil provided with a winding form, the latter is coupled to the shaft of a wire feeder of a welding machine, thus drawing the welding wire from the winding form to be fed to a welding head. On the other hand, for a coil without a winding form, the coil is mounted on a winding form such as a spool or on a feed adapter, which is then coupled to the shaft of the wire feeder (see, for example, Japanese Laid-Open Patent Applications No. 111,770/1993 and No. 200,553/1993).
FIG. 16a shows a feed adapter 12 used in a conventional arrangement. A user removes a wrapping material from a welding wire coil constructed in the manner mentioned above, and mounts it on the adapter 12, which is in turn mounted on a feeder 13 of a welding machine. Before a welding operation can be initiated, the welding wire must be drawn from the feeder 12 and passed through a feed roller pair 15, a conduit liner 16 and a welding torch 17 of the welding machine. The coil is consumed with the progress of the welding operation, and when the remaining wire on the feed adapter 12 is substantially the wire in the lowermost tier of the coil, it springs and breaks up in a manner illustrated in FIG. 16b. This may cause the welding wire to be tangled with the shaft associated with the feed adapter, and once tangled, the wire feed operation must be interrupted disadvantageously.